I was in two minds about this, Threeb, even though I've tried playing it myself from time to time.
I haven't found a dictionary entry for roid meaning steroid without an apostrophe in front of it. A couple of dictionaries have roid rage with no apostrophe, but don't have roid by itself. And as you know, I'm not keen on "words" that only ever appear as part of a phrase. However, in this case, it does seem likely that people discussing roid rage might also use roid to name the alleged cause of the problem. And as it is a subject matter of fairly recent origin, the lack of dictionary support may be because the usage hasn't been picked up on by the dictionaries yet.
I also found from the Shorter Oxford that roid can mean "stout, strong; violent, rough" and "rude; large, unwieldy". These meanings are described as long obsolete except for dialect, but they help tip the balance.
So, I will add roid to our list.